Outside calipers.



No. 720,773. PATENTED FEB. 17, 1903.

M. H. BALL.

OUTSIDE UALIPERS.

AYPLICATION FILE-D JULY 11', 1902, no menu.

UNITED STATES PATENT OFFICE.

MARTIN H. BALL, OF WATERVLIET, NEW YORK.

OUTSIDE CALlPERS.

SPECIFICATION forming part of Letters Patent No. 720,773, dated February17, 1903 Application filed July 11,1902. Serial No. 115,213. (No model.)

To (055 whont it may concern:

Be it known that I, MARTIN H. BALL, a citizen of the United States,residing at \Vatervliet, in the county of Albany and State of New York,have invented a new and useful Improvement in Outside Calipers, of whichthe following is a specification.

The object of this invention is to provide a caliper to accurately andconveniently take all outside measurements that are customarily takenwith the ordinary plain and spring outside calipers in common use andalso to take measurements as indicated in the accoin panying drawings,as thickness of metal in a bar, as shown, when the operator does nothave access to either end of same, or to any place along the sides wherethe bar is no thicker than at the portion to be measured that has to bespanned by the calipers before reaching the portion to be measured. Iattain these objects by the mechanism illustrated in the accompanyingdrawings, in which- Figure 1 is a front elevation, and Fig. 2 anenlarged vertical section, of a part of the calipers on the line A B.

Similar letters refer to similar parts throughout the several views.

F and F are the legs, connected near their upper ends by the spool S,which forms the joint, and are all held in place by the mainspring M.

- The spool S is not shown in detail in the drawings, as it is not apart of my invention and is only used to show a formof calipers to whichmy improvement can be attached.

G is the adj listing-screw with knurled head, to be operated by thumband fingers. The thread being made left hand makes the calipers operatethe same as those in common use and avoids confusion when using bothkinds alternately.

C and D are studs passing through holes in the legs and are riveted downover small washers H H on the opposite side, the parts being drawntogether enough to secure a slight amount of friction, so they will keeptheir position when the legs are drawn apart in transferring. Throughlug O is tapped a hole through which screw G passes, and into stud D asocket is made to receive the point of screw G.

E is a barrel bored out to receive the spiral spring J at the end thatjoins stud O and threaded at the opposite end to fit screw G and isprevented from turning with screw G by its being fitted around stud C,as shown in Fig. 1.

In calipering over a flange, as shown in Fig. 1, the legs are drawnapart until their points pass over the flange. The screw G is thenturned until the points come in contact with the part to be measured,after which the legs are drawn apart and held by hand until the pointsclear the object, when they are allowed to come back to their originalposition, the screw G leaving the socket in stud D when the legs weredrawn apart and drops back in its place again when they are released,thus leaving the legs the exact distance apart that they were when theywere in contact with the object measured. A scale may now be applied atthe points of legs, and the size ascertained.

The spring J has a tendency to force the barrel E and stud C apart, thuscreating a slight friction, preventing the screw G from turning from anyjar that it might receive when transferring and also taking up allbacklash. I V

The screw G being forced to the bottom of the socket in stud D bymainspring M always has the same amountof pressure applied, andconsequently this caliper is more accurate than any kind oftransfer-caliper that has its movable leg put back by hand.

When calipering lathework in motion this caliper will not catch, bend,or lose its size, as others do when crowded over the work while the workis too large; but the adjusting-screw G will come partly out of socketin stud D and spring back to its former place when taken from the work.

When not in use, the legs may be drawn apart enough to bring the screwGout of socket in stud D, when the screw may be tipped, as shown by thedotted lines in Fig. 1, and the points of legs allowed to come together,releasing to a great extent the mainspring M, which has a tendency toprolong its life.

I am aware that the way of making and attaching the legs F F, spool S,and mainspring M and also the way of attaching studs 0 and D to legs isnot new, but has been used for several years, and I do not claim this asmy invention; but

What I do claim as my invention, and desire to secure by Letters Patent,is-

1. The combination in outside calipers of the legs thereof, anadjusting-screw having socketed engagement with one of the legs, a studC pivotally mounted in the other leg and having a transverse aperturethreaded to receive said screw, a barrel E screw-threaded at one end tofit said adjusting-screw and at the other end shaped to abut against andfit around said stud O the end of said barrel which abuts against saidstud being bored out to receive a spiral spring, and said spring bearingat one end against the bottom of the bored-out portion of said barreland at the MARTIN H. BALL.

Witnesses:

H. O. KIMMEY, OTIS P. STONE.

